Dampening mechanism



Feb. 11, 1941. y H E GQLBER 2,231,666

DAMPENING MECHANISM Filed May l1, 1938 5 Sheets-Sheet l 5 Sheets-Sheet 2 '1-1. E. Gamm-:R

Filed may 11, 193s DAMPENING MEcHANIsM Feb. 11, 1941.

H. E, GOLBER 2,231,665

DAMPENING MECHANISM Feb. 11, 1941.

Filed May ll. 1938 5 Sheets-Sheet 3 Patented Feb. 11,1941

DANWENING MECHANISM Hyman E. Gelber, Ghc'ago, Ill.,

Miehle Printing Press assignor to The & Manufacturing Company, Chicago, Ill., a corporation of Illinois Application May 11, 1938, Serial No. 207,241 9 claims. (el. 10i- 147) The invention relates to dampening mechanism for lithographie printing presses and other reproducing apparatus and has particular reference to dampenng mechanism which will selectivelycontrol the volume of moisture to be supplied to the printing plate of a lithographie offset ress.

In rotary lithographic presses, for example, it is necessary to adequately dampen the surface of the printing member in order to prevent the ink from adhering to the non-printing areas of. the surface, namely, to those areas which are free of any printing image.

If the film of moisture applied by the dampening rollers to the printing surface of'the lithographic plate the plate, then portions of the plate which solids or darker tones of the subject to be printed there will be an excess of moisture. In other words, the plate will become ooded with moistureparticularly at those areas which correspond with the dark tones and solids and consequently such excess supply of moisture will tend to repel the ink from the printing image where the ink is to adhere, resulting in a defective print.

Furthermore, when there is an overabundance of moisture on the plate the fluid will eventually become mixed with the ink so that after a number of impressions have been pulled, the solid blacks and dark tones will assume a grey appearance. In order to rectify this defect the operation of the press has to be interrupted and the inking and dampening mechanism reconditioned.-

All this is-due to the heretofore physical impossibility of positively and accurately controlling the supply of moisture to the different sections of the printing plate.

Apparatus heretofore most commonly used for supplying moisture to planographic printing Y plates consists essentially of a water fountain, a fountain roller, and water distributing or dampening rollers which contact the surface of the printing plate. The latter are intermittently supplied with a volume of moistureA byineans of the ductor roller which alternately contacts with the fountain roller and the dampen'- -ing rollers. This class of apparatus however, has not vproven entirely satisfactory mainly because of the difficulty experienced in obtaining the desited in maintaining constant the supply of such iiuid to the dampening rollers. to the contact of; the damp 55 lprinting platea certain amount of it stands to correspond with the enmg rollers with the ink is picked to maintain clean up by these rollers and eventually transferred to the fountain roller, consequently it is impossible the fluid in the fountain, as well as the various rollers. In time the molleton material, with which the dampening rollers are covered, becomes saturated and clogged with ink, necessitating frequent interruptions in the printing operations in order to replace such clogged rollers.

One of the primary objects of my invention 10 therefore, is to provide novel means whereby the required volume ,of moisture to be supplied to any particular section of the printing platecan be predetermined and maintained, thereby eliminating all of the defects pointed out herein.

Another object of the invention resides in the provision of dampening mechanism for supplying moisture to planographic printing plates which will overcome the major defects in apparatus heretofore used, which will be of relatively simple construction, and applicable to presses now in use.

A further object is to provide dampening mechanism which will maintain the water in the fountain clean and free of ink.

Another object resides in the provision of dampening mechanism that will supply a controllable quantity of moisture to planographic printing surfaces and which may be uniformly distributed over the entire width of the printing 30 member or varied in amount locally to suit particular requirements of certain areas on the printing surface without adversely affecting adjacent areas.

A more specific object is to provide d ampening mechanism having a plurality of water supplying nozzles and independent regulating means for each nozzle so that the amount and distribution of moisture to the printing member can be varied to suit conditions.

A still further object is to provide dampening mechanism including a plurality of nozzles supplying a controlled amount of water to a water roller during every revolution thereof and which is received by the water roller at a different point on its periphery for each revolution.

With these and various other objects in view 'the invention may consist of certain novel features of construction and operation as will be more fully described and particularly pointed out in the specification, drawings and claims appended hereto.

In the drawings which illustrate an embodiment of the invention and wherein like reference characters are used to designate like parts- Figure 1 is a diagrammatic illustration showing the association of the present dampening mechanism with the printing cylinders of a press;

Figure 2 is a vertical sectional view showing one of the water pumping devices comprising the present invention;

Figure 3 is a sectional View showing thewater pumping device of Figure 2 with the plungers in still another position of operation;

water from the nozzle; and

Figure 5 is a fragmentary elevational view showing the positioning of the devices adjacent each other to comprise the present dampening mechanism.

printing plate mounted manner. Ink is applied to inking rollers I2 forming the printing couple. In contact with the printing plate are dampening rollers I6, preferably covered with molleton material and which in turn contact a distributing roller I1,

port. However, the frame member can be readily released merely by turning the nut 3|) in case it is desired to remove the device for cleaning or repair.

The body form a bore 33 extending completely ythrough the body portion and a recess 34 terminating short of the lower end of said body portion. The

ner the plunger 38 for all portion 28 is cored longitudinally to is adapted to reciprocate vertically within the recess 34. The plunger 31 is formed with a longitudinal groove 40 and with a transverse passage 4|. munication with recess 34 through passage 35 when the plunger is .located in its lowermost position, which position of the plunger locates the passage 5| in alignment with nozzle 35, as shown in Figure 4. Fixedly secured to the upper end of each plunger are members 42 and 43, respectively, for retaining a coil springon said plunger. The coil spring 44 on the plunger 31 is confined between the Ibody portion and 'the member 42, whereas, the coil spring 45 on plunger .38 is confined between the body portion and the member 63.

Pivotally secured to the upper end of member 42 as at 46 isa bell crank lever 48 pivotally supported by the frame member 21 at 41. One arm of the bell crank has a U-shape in order to provide clearance for the flattened portion 3| of the screw 30' whereby said screw can be rotated positions of the bell crank. The other arm of said bell crank carries a roller 50 having contact' with the cam 5| carried by shaft 52. Pivotally secured to member 43 as at 53 is a bell crank 56| pivotally secured to the frame at 55. The horizontally disposed arm of said'bell crank is limited in its upward movement by the adjustable screw 56 having the knurled portion 51 and is suitably threaded in the'boss 5B4 formed integral with and projecting from the -frame member 21. The vertical arm of said bell crank carries the roller -BI having contact with cam 5| carried by shaft 52.

cated through actuation of the respective bell cranks by the cam 5|. In Figure 2 the plunger 31 has just been raised as a result of the counterclockwise rotation of the cam 5|, since it will be seen that roller 50 is in contact'with the lower part of the cam, thereby making possible upward movement of the plunger by the tension exerted by spring 44. With the plunger in its uppermost position the lower end of bore 33 is' in communication with the fountain. As-the water level in the fountain is above the lower end of the plunger, water will rise within said bore and fill the passage 35. Continued rotation of cam 5| will bring the lower part of the cam in alignment with roller 60, thereby resulting in upward movement of plunger 38 to the extent permitted by the adjusting screw 56. Upward movement of the plunger will result in drawing water within the recess 34. It will be observed that this up ward movement of the plunger lling the lower end of the recess 34 with water takes place while the plunger 31 is located in its uppermost position, in which position of the plunger 31 the said recess 34 is in communication with the water in the fountain through the passage 35.

When the shaft 52 has rotated to bring roller 50 into contact with the high portion of the cam 5| the plunger 31 will be forced downwardly, whereupon kthe passage 35 will have communication with the nozzle 36 through the passage 4| and the longitudinal groove 40. When the roller 60 is actuated by the high portion of the cam, which will take place upon continued rotation of shaft 52, plunger 38 will be forced downwardly tor force the water out of recess 34. As described the discharge nozzle 36iis in communication with said recess and the water forced from the recess by downward movement of the plunger 38 will The groove has comscrew 56. This screw limits the upward movei ment of plunger 38 and thereby determines the capacity of the recess 34. The recess will lbe entirely lled with water as a result of upward' movement of said plunger but the quantity of water .within'the same will be in proportion to the movement of the plunger. Since plungers 31 and 38 are both actuated by the same cam, their movement occurs in timed relation with eachv other and the downward movement of plunger 38 will always take place while plunger 31 is located in its lowermost position, since in this position said plunger provides a passage from the recess to the discharge nozzle. The water discharged from the nozzle when the plunger 38 moves downwardly will be predetermined in amount according to the adjustment of screw 56.

The cam shaft 52 and the water roller 20 are rotated out of synchronism with each other so thatthe water from a nozzle 3B will be delivered to the roller at a different point on its periphery for each revolution. Also, as previously described,

the Water roller is vibrated, that is, said roller has axial reciprocating movement simultaneously with its rotary movement. The combined result of these operations is to properly distribute the water over those areas on the roller to which it is applied, and since each water supplying device is adjustable for varying the amount of water delivered thereby, certain portions on the water roller can be supplied with more or less water,

depending on the requirements of the corresponding portions on the printing plate. In fact, it is possible to restrict the water from certain nozzles to one drop every two or three revolutions of the cam 5I or the screw can be set to entirely shut off the discharge of water from a device. On the other hand, the adjusting screw,can be released to allow plunger 3B to move upwardly'to its maximum'extent, whereby the nozzles will deliver a relatively largeV quantity of water every revolution of the cam shaft.

After adjustment of the water feeding devices to suit the particular requirements oi? a printing job the vdevices will continue to operate for a definite period at the same rate of feed and therefore it is unnecessary for an operator to constantly watch the operation of the mechanism or the moisturecondition of the printing plate. Each device is secured to a common support by its fastening means and accordingly the devices are removable individually to permit cleaning and repair and are also shiftable along their support so that certain devices can be grouped closer or spaced farther apart 4than others. This feature in combination with the metering of the water discharged by each device and the fact that the discharge is supplied to the water roller at a different point on its periphery for each revolution produces a thorough distribution of the water and in addition makes possible select application to suit the most exacting requirements.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawings, as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

l. A liquid feeding device for use in dampening mechanism, comprising a body portion having a discharge nozzle, a recess vformed in said body portion, a plunger mounted for reciprocation in said-recess, and means actuated in timed relation with the movement of said plunger for connecting the recess alternately with a source of liquid supply and with said nozzle, whereby said plunger in one direction of movement fills said recess with water and in the other direction of movement causes said water to be discharged from the nozzle.

2. A liquid feeding device for use in dampening mechanism, comprising a body portion having a discharge nozzle, a recess formed in said body portion, a plunger mounted for reciprocation in said recess, and means actuated in timed relation with the movement of said plunger for connecting the recess alternately with a source of liquid supply and with said nozzle, said plunger having movement in an upward direction when the recess is connected to the source of liquid supply to,

portion, a plunger mounted for reciprocation in said recess, means actuated in timed relation with the movement of said plunger for connecting the recess alternately with a source of liquid supply and withA said nozzle, whereby the ,plunger in one direction'of movement fills said recess with water and in the other direction oi movement causes said water to be discharged from the nozzle, and adjusting means for varying the reciprocating stroke of said plunger to vary the capacity of said recess and therefore the quantity of water forced therefrom by the plunger and discharged from the nozzle.

4. A liquid feeding device for use in dampening mechanism, comprising a body portion having a discharge nozzle, a recess formed in said body portion, a plunger mounted for reciprocation in said recess, means actuated in timed relation with the movement of said plunger for connecting the recess alternately with a source of liquid supply and with said nozzle, said plunger having movement upwardly when the recess is connected with the source of liquid supply to thereby iill the recess with'water and said plunger moving downwardly when the recess is connected with the nozzle to cause said water to be discharged from the nozzle, and adjusting means for varying the securing the same to a support positioned above and extending the length of said reservoir, the

' lower end of each said device having an opening therein below the level of the liquid in the reservoir, and each device including a reciprocating plunger pump mounted for movement within a recess and having operation to alternately fill same from the device, and means for actuating said reciprocating pump of each device.

6. In dampening mechanism, the combination with a reservoir containing a liquid, of a plurality of liquid feeding devices having operation to discharge a quantity of liquid for each actuation thereof, means on each device for releasably securing the same to a support positioned above and extending the length of said reservoir, the lower end of each said device having an opening therein below the level, of the liquid in the reservoir, and each device including a reciprocating plunger pump mounted for movement within a recess and having operation to alternately fill said recess with liquid and force the liquid therefrom, the said filling operation drawing the liquid from the reservoir through the opening in the Alower end of the device and the forcing of the liquid from the recess causing discharge of the same from the device, and cam meansv extending the length of said reservoir for actuating the reciprocating pump of each device.

7. In dampening mechanism, the combination with a reservoir containing a liquid, of a plurality of'liquid feeding devices having operation to discharge a quantity of liquid for each actuation thereof, meanson each device for releasably securing the same to a support with the lower end of the device immersedin the liquid in the reservoir, each device including a discharge nozzle and a movably mounted plunger forming a pump -for the liquid whereby the liquid is withdrawn from the reservoir and discharged through said discharge nozzle, means actuating the said plunger, and other mea-ns having actuation in timed relation with said plunger for controlling the withdrawal of the liquid from the reservoir and the delivery of the same to the discharge nozzle.

8; A liquid feeding device for use in dampening mechanism comprising a body portion having an opening in the lower-end below the level of the liquid to be fed thereby, a recess in said body portion having communication with said opening,

la discharge nozzle extending from the body portion, a plunger mounted for reciprocation in said recess, said plunger forming a pump for the liquid whereby movement in one direction will draw liquid through said opening to ll the recess and movement in the opposite direction will force the liquid therefrom, and a second plunger having reciprocating movement in timed relation with said iirst mentioned plunger, said second plunger having operation to connect the recess with the discharge nozzle when movement of said first mentioned plunger is in a direction to force liquid therefrom.

9. A liquid feeding device for use in dampening mechanism comprising a body portion having its lower end positioned below the level of the liquid to be fed thereby, a plunger mounted for vertical movement within a recess formed in said body portion to provide a pump for the liquid, a second plunger mounted for vertical movement within a passage extending through the body portion, a discharge nozzle leading from the upper end of said passage and projecting from the body portion, said passage providing an opening below the liquid level and which lcommunicates with the lower end of the recess, whereby liquid may ilow from the reservoir into said recess, said second plunger having a groove extending longitudinally thereof, and means reciprocating said second plunger in timed relation with said first mentioned plunger whereby the said plunger in one position of movement will connect the recess with said opening and in its other position of movement will connect the recess with the discharge nozzle.

o HYMAN E. GOLBER. 

